This application claims the priority of Korean Patent Application No. 2004-49727, filed on Jun. 29, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to an image sensor module structure and a method of manufacturing the image sensor module structure, and more particularly, to an image sensor module structure comprising a wire bonding package, and a method of manufacturing the image sensor module structure.
2. Description of the Related Art
Image sensors are semiconductor electronic devices that convert optical information into electrical signals. Examples of Image sensors include charge coupled device (CCD) image sensors and complementary metal oxide semiconductor (CMOS) image sensors. As cameras, camcorders, personal computer (PC) cameras, and surveillance cameras are digitalized, applications of image sensors are increasing. In particular, a tremendous growing demand for mobile devices equipped with image sensors, such as camera phones, has accelerated the demand for smaller, thinner image sensor modules.
FIG. 1 is a schematic sectional view of a conventional image sensor module structure comprising a wire bonding package. Referring to FIG. 1, an image sensor module structure 100 includes an image sensor package composed of a substrate 110, an image sensor chip 112, and wires 116, a housing body 120, an infrared ray (IR) cut filter 130, and a lens assembly 140. The housing body 120, the IR cut filter 130, and the lens assembly 140 are collectively referred to as a housing.
The image sensor package is a wire bonding package composed of the substrate 110, the image sensor chip 112, and the wires 116. A light receiving area 114 is formed at the center of a top surface of the image sensor chip 112, and the image sensor chip 112 is mounted on the substrate 110. The image sensor chip 112 and the substrate 110 are electrically connected together by the wires 116. The wires 116 connect bonding pads 115 formed outside the light receiving area 114 to interconnection pads 111 formed along an edge of the substrate 110.
The housing body 120 attached on the substrate 110 includes an upper sidewall 120a and a lower sidewall 120c. A middle sidewall 120b is disposed between the upper sidewall 120a and the lower sidewall 120c and allows the IR cut filter 130 to be attached thereto. A lens holder 146 is adhered to the inside of the upper sidewall 120a. The upper sidewall 120a of the housing body 120 and the filter 130 define a first cavity into which the lens assembly 140 is inserted. The lower sidewall 120c of the housing body 120 and the filter 130 define a second cavity over the image sensor package composed of the substrate 110, the image sensor chip 112, and the wires 116.
In the conventional image sensor module structure 100, the housing body 120 may have various structures. However, the various structures of the housing body 120 share a common thing; the lower sidewall 120c in the image sensor module structure 100 including the wire bonding package is attached to an outermost edge of the substrate 110, more specifically, to a top surface of the substrate 110 outside the interconnection pads 111 to which the wires 116 are connected. Further, a height h3 of the lower sidewall 120c is greater than the sum of a height h1 of the image sensor chip 112 and a loop height h2 of the wires 116 so that the wires 116 can reside in the second cavity (see U.S. Pat. No. 6,389,687).
The filter 130 is inserted and attached to the middle sidewall 120b. As shown in FIG. 1, the middle sidewall 120b may inwardly project as compared with the upper sidewall 120a and the lower sidewall 120c so that the filter 130 can be easily inserted into the middle sidewall 120b. The filter 130 may be fully inserted into the middle sidewall 120b, or may be disposed beyond the projecting middle sidewall 120b. That is, the filter 130 is spaced from the image sensor chip 112 by a predetermined interval (h3-h1) due to the second cavity.
The lens assembly 140 includes a plurality of condenser lenses 142, spacers 144, and the lens holder 146. Adjacent condenser lenses of the plurality of condenser lenses 142 are spaced apart by each spacer 144, and the plurality of condenser lenses 142 are attached to the inside of the lens holder 146. A screw thread is formed along an outer wall of the lens holder 146, and a screw thread is also formed along an inner wall of the upper sidewall 120a, so that the screw threads can mesh with each other.
In the conventional image sensor module structure 100, the image sensor chip 112 is attached to the top surface of the substrate 110. The interconnection pads 111 to which the wires 116 are connected are formed outside the image sensor chip 112. The lower sidewall 120c is attached outside the interconnection pads 111. Accordingly, an area d1 for the interconnection pads 111 and an area d2 for the lower sidewall 120c as well as an area for the image sensor chip 112 should be prepared on the top surface of the substrate 110. The areas d1 and d2 result in an increase of a horizontal size of the image sensor module structure 100, thereby making it difficult to reduce the size of the image sensor module structure 100.
Conventional efforts have been made to reduce the size of the substrate 110 by attaching the lower sidewall 120c very close to the interconnection pads 111. Consequently, if slight misalignment occurs during a process of attaching the housing body 120, the wires 116 may be damaged.
Efforts have also been made to prevent impurities from entering the cavity and remaining on the light receiving area 114 by attaching the housing body 120 under vacuum. This vacuum process makes the manufacturing process more cumbersome. In addition, contact portions between the lower sidewall 120c and the substrate 110 and between the middle sidewall 120b and the filter 130 must be sealed elaborately, thereby making the manufacturing process more difficult.